The present invention relates generally to an absorbent article, and particularly to an absorbent article having a mixture that generates heat when exposed to air and/or moisture.
All manner and variety of devices or appliances configured for absorption of body fluids, such as menses, are well known. Sanitary napkins are the most frequently used of these devices. The prior art is replete with patents relating to protective pads and sanitary napkins for the absorption of body fluids and protecting the undergarment from staining. It has been suggested that from 20-25 percent of all sanitary napkins leak. A contributing factor to the leakage is that menses is a viscous fluid having aqueous and mucus-like components.
A problem in the performance of the absorbent is that the more viscous the material the slower the rate of absorption. Basically, the low viscous materials readily pass through the cover of the sanitary napkin and are absorbed by the absorbent. The higher viscosity materials in the menses may not be absorbed and can remain on the cover. Alternatively, the higher viscosity materials may be absorbed but remain at or near the point of insult occluding absorption of the lower viscosity materials. This limits the effectiveness of the absorbent and the utilization of the absorbent capacity of the sanitary napkin. Moreover, the absorbent may contain superabsorbent materials which preferentially absorb the aqueous constituents from low viscous materials thereby increasing the viscosity of the remaining material. This exacerbates the problem of the absorbent to absorb the viscous components of the menses.
Until now, surfactants have been used to improve the absorption of body fluids. One or more of the materials used in constructing the sanitary napkin, such as the cover and/or absorbent, have been treated to improve the material wettability. The problem of using a surfactant is that the surface energy of the coated material is modified but the surfactant does not appreciably modify, if at all, the viscosity of the body fluid. Thus, the higher viscosity materials are still not efficiently absorbed.
Accordingly, there is a need for an absorbent article, such as a sanitary napkin, which can modify the viscosity of a viscous material so that it can be absorbed.
This invention contemplates adult feminine hygiene articles for absorbing body fluids from a wearer and comprises a liquid permeable cover; a liquid-impermeable baffle; an absorbent enclosed between the cover and the baffle; and heat cell material as an integral part of the adult feminine hygiene article, for heating the absorbent, the heat cell material being free to receive menses from outside the adult feminine hygiene article, the heat cell material being reactable with menses to generate heat such that, in use, heat is generated when menses from the wearer is received at the adult feminine hygiene article, the heat being effective to lower the viscosity of the menses, thereby increasing the capability of the adult feminine hygiene article to absorb the resulting lower-viscosity menses. The adult feminine hygiene article has a liquid absorption capacity of about 1 milliliter up to about 30 milliliters.
In some embodiments of the invention, the heat cell material of the adult feminine hygiene article comprises a chemical mixture distributed throughout the absorbent, the chemical mixture being reactable in the presence of aqueous liquid to generate heat. The chemical mixture can be distributed randomly or substantially uniformly at multiple locations throughout the absorbent.
In some embodiments, the absorbent includes superabsorbent materials which absorb aqueous constituents from lower viscosity materials.
In some embodiments, the heating apparatus includes an air and moisture-permeable material enveloping the heat cell material.